Focus stacking is a process of blending multiple photos of the same scene together, where each photo is focused on different part of the scene. The final blended picture is created by choosing the sharpest area from every photo in the stack. In macro photography, closer the object is to the camera, the lower the depth of field is, which leads to only small part of the scene being in-focus. In order to capture the sharpest possible image, photographer needs to take multiple photos of the object and stack all of the images into the single.

We provide the first free online focus stacking software on the market which lets you do so! In just few simple steps get the sharp photo from your pictures! No complex understanding of large-scale software nor any installation are needed. Completely free and online. All you need is a web-browser. You can get your images stacked on your home laptop or smartphone, all of these platforms are supported.

Get your stacked photo in just few steps:

• Press "Add" button and choose your pictures!
• Choose the alignment method: Standard usually works fine, however in some cases our new Beta method outperforms the standard one. Trying different alignment methods can lead to better results.
• Select the right reference picture. In general, reference should be the picture which contains the large part of object in focus. Sometimes playing around with the reference image improves the final result!
• Click "Stack" to get your final picture.
• Download focus-stacked picture and enjoy!

Why do we need stacking?

In a laymen terms, the Depth of Field is the distance between the nearest and the farthest objects that are in acceptably sharp focus. It is a property of the set of optical components (mostly lenses), which can be calculated based on the focal length, distance to subject, aperture and the size of the circle of confusion. From physics of light perspective, DOF can be expressed via following formula for a single lens:

• u is the distance from the subject to the lens,
• N is the so called f-number (denoted to as well as f-stop, f-ratio),
• c is the diameter of the circle of confusion,
• f is the focal length - it is a distance of the point where life-rays converge and form sharp image to the optical centre of the lens,
• D is the diameter of the aperture (entrance pupil).

On the first site the formula above might look scary, but we are about to break-it down to simple layman terms in order to explain the elementary physics behind the macro photography. So our final Depth of Field (or portion of the scene which is in-focus) is increasing withu (distance between subject and the scene),N (f-number),c (diameter of circle of confusion, which is a merit of how "blury" final image can be).

At other hand, to increase the portion of the scene in focus, we can decrease the D - aperture diameter of the optical setup. Another property impacting the Depth of Field is the focal length. The bigger the focal length of the lens is, the lower the depth of field is. This is caused by the fact that if we have big distance between the optical center and the sensor (this distance is the focal-length), light-rays coming from distant objects will hit the lens at very shallow angles and thus they will mostly converge before the sensor, thus will appear as blury. Macro lens focal powers usually range from around 50mm up to 200mm (this may vary on brand-per brand basis). Having a macro lens of higher focal lengths range gives us higher price tag and also the option to stand bit further from the object ( as light rays from more distant objects come at shallower angles and they need more room behind the lens to converge). Having a macro lens from the lower focal length range means we need to get closer to the object, which in fact may be quite difficult in some situations if the scene is not artificial.

So how can we improve amount of scene in focus in macro photography? As noted from above, we can't increase the distance to the object u as we want to stay close. We can try to decrease the aperature diameter D, but this would lead to smaller angle of view and our anyhow small scene would shrink even further. Can we try to decrease the focal-length? Unfortunately, this would lead us not being able to focus our object which is close to the objective itself, as the rays of objects close to the lens would converge behind the sensor. Therefore our option is to keep the aperture size so that we can capture sufficient part of the scene, along-with preserving the focal-length on a level (maybe around 90mm) which allows us to go close-enough to the object, whereas trading sharp close-up picture for a shallow depth-of-field. So there is a trade-off we need to make between depth-of-field and the sharpness of close-by objects. Gladly, there is a way around! We can snap multiple pictures and computationally stack them together to produce final sharp image!

What lens do I need to capture macro?

Generally speaking, there are many lenses on the market devoted for macro. Macro lens is a lens which provides a magnification ratio of at least 1:1. This means that the object appears exactly as it is in the real life. To capture the very detailed pictures (e.g. an eye of a fly) we need a ratio which is higher than 1:1. There are many lenses which can provide even higher ratio, like 3:1 and above. This means that the object appears to be three times its original size on the sensor. When considering a macro lens purchase, our recommendation is to be ware of "fake" macro lenses which have a ratio of not at least 1:1, like 1:2 or 1:3 and claim to be macro - they are not, true macro needs to be at least 1:1.

Price tag ranges also significantly. One can find also cheaper ones starting at around 100$, ranging up to more than 3000$ per lens. Price tag is impacted by the focal power of the lens. Higher the focal power, higher the price usually is.

How to snap high-quality macro photos?

To produce one of those all-sharp close up pictures, one simply needs to put in a lot of patience and bit of a try-and-fail approach initially. All of these sharp images which we can see out there are never a product of just a single photo. It is usually the stack of multiple images. The amount of images in the stack varies significantly. It can range anywhere from just two images to easily more than 100. Our recommendation is to always fix up your camera first next to the scene. As the final sharp image almost always requires stacking, by fixing up the camera we maximize our chance of producing sharp image at the end of the process as it is cumbersome for the software to deal with elements like handshake and scene variation.

Having our camera fixed (either on the tripod, or by any other means), we start by focusing the part of the object which is closest to the camera. Then we slowly move the focus to sweep through the scene and take a picture of every subpart of the scene being in focus. For more details on how the images of a stack look-like and an example checkout our stacking manual.